Shooting out of the blocks just in time for London 2012, Fast Girls whips up a bit of Olympics excitement with its girl power story of an unfancied relay team striving for glory.

Being Human's Lenora Crichlow leads the cast as Shania Andrews, a runner who escapes from her concrete housing block to train with corner shop owner Brian (Phil Davis). She's got raw talent and lightning speed, with a sparky attitude to match. This leads her to gets a shot at the big time when she's invited to join the Team GB relay group for the World Athletics Championships (copyright restrictions prevent use of the Olympics name).

Among her new teammates are heralded sprinter Trix (Lorraine Burroughs), mohawked Sarah (Dominique Tipper), man-crazy Belle (Lashana Lynch) and golden girl Lisa (Lily James). Shania soon clashes with Lisa, who's less talented - but her father (Rupert Graves) - a former WAC gold medal winner - is involved in the team selection.

One is from the wrong side of the tracks, the other is a posh thoroughbred, and that's enough to provide friction within the team before the Olympics championships arrive.

It doesn't take a brain surgeon to figure out where Fast Girls is going. It follows the expected trajectory for a sports film, with romance (Shania and Bradley James's physio Carl), training montages, forged and broken friendships and triumph against all odds coming into play.

This is aided by strong performances from the cast, particularly Crichlow's Shania, a plucky underdog who's easy to root for. The best lines, though, go to Lynch's runner Belle, who steps into scenes to dispense zinging one-liners.

First-time director Regan Hall captures the track action with zip and sweaty verve, and crucially all his leading ladies look the real deal as pro athletes. There are duff moments in the film, notably the flimsy romantic subplot that barely registers. Merlin's James is given little to do but give the girls rubdowns and loiter in the background to catch Shania's eye.

This won't go down as a classic, and frankly it's a giant slice of sports movies cheese, but it's admirably earnest and always entertaining.